S2 speedometer

[Ken J Greetham]

1989 S2 speedometer. Can anyone help? My speedo works but the odometer numbers don't. can it be repaired?
Also my engine runs better when the shuttle valve that sits on the top of the inlet manifold, is disconnected. why is this?

[S2Mike]

Is the speedo mileometer stopped at some number ending with a 9, like 49999, where it has to turn more than 1 or two tumblers. ?
It has been mentioned by a few on here, all it needs is a drive over a cobble street or a sharp tap on the dashboard, to unstick it. The resistance of the extra tumblers to turn pushes the "gearing" out of touch.
Although if you are on restricted mileage insurance, we wont tell anyone..

[Roy C]

Ken J Greetham said:

...my engine runs better when the shuttle valve that sits on the top of the inlet manifold, is disconnected. why is this?

Do you mean the Air Bypass Valve (AKA Idle speed control valve)?
This works like a choke to introduce more air (and therefore fuel) into the system when the engine is cold.
It may be sticking open due to 20 years of crud, but it's easy to take apart to clean.

If you mean the Throttle Potentiometer, see here: http://www.tvrsseries.com/throttlepot/throttlepot....

[phillpot]

Roy C said:

It may be sticking open due to 20 years of crud, but it's easy to take apart to clean.

Agree except if sticking disconnecting wouldn't help? Possible temperature sender that tells ECU the engine is warm is cream crackered or wire fell off?


Back to the speedo, if the bumpy road doesn't fix it I believe these people can, never used them myself but seem to recall a comment or two that they don't always live up to their name